Food patty molding machine

Abstract

A high speed food patty molding machine, for manufacturing hamburger patties or other molded food products, comprising two large piston pumps operating in overlapping alternation to feed moldable food material continuously to a manifold that in turn feeds a cyclic molding mechanism. The molding mechanism need not operate synchronously with the pumps; the volumetric capacity of each pump is several times larger than the volume of meat or other moldable feed material required to fulfill a molding cycle. The pressure of the food feed is adjustable for different product requirements. The molding mechanism includes an elevator system for raising the complete mold assembly to a changeover position.

I claim: 
     
       1. A high speed food patty molding machine comprising: a multiple-cavity, cyclically operable molding mechanism .Iadd.which requires a given volume of food material in each cycle of operation, the molding mechanism .Iaddend.having an inlet for supplying food material simultaneously to all of the cavities, the molding mechanism inlet being closed for a major portion of each molding cycle;   two food pumps, each pump comprising a fixed cavity having an intake opening at one end and an outlet opening at the other end, a plunger aligned with the intake end of the cavity, and drive means for moving the plunger between a retracted ready position clear of the intake opening in the cavity and a pressure position in which the piston is advanced inwardly of the cavity beyond the intake opening toward the outlet opening;   supply means for supplying moldable food material to the intake opening of each pump cavity whenever the plunger for that pump is in its retracted position;   a manifold connected to the outlet openings of the two pump cavities and having an outlet passageway connected to the molding mechanism inlet to supply a substantially unrestricted flow of food material thereto;   actuating means for actuating the pump drive means in overlapping alternation so that at least one pump cavity always contains moldable food material under a given minimum mold-filling pressure and, when the material in one cavity reaches a given minimum volume, both pump cavities contain moldable food material under the aforesaid mold-filling pressure for a limited pump changeover interval;   .[.and.]. valve means for sealing off the outlet opening of each pump cavity from the manifold whenever the plunger for that pump is moved toward its retracted position, in an overlapping cycle such that both outlet openings communicate with the inlet to the molding mechanism during a part of said changeover interval, thereby affording a continuous supply of moldable food material, under continuous pressure, at the inlet of the molding mechanism.[...]..Iadd.; .Iaddend.   .Iadd.the capacity of each food pump cavity being several times said given volume so that each pump supplies the molding mechanism for a plurality of molding cycles without requiring an intake of additional food material;   and the drive means for each food pump comprising a fluid pressure actuated power cylinder and a piston which advances the plunger and the food material in the food pump cavity during a part of each mold cycle in which the mold fills with food material and stalls against the food material trapped in the food pump cavity during a part of each mold cycle after the mold is filled. .Iaddend.   
     
     
       2. A high speed food patty molding machine, according to claim 1, in which the valve means is incorporated in the manifold and comprises: a valve cylinder extending across the outlet openings of both food pumps, the valve cylinder including at least one inlet opening for receiving food material from the food pumps and an outlet opening communicating with the manifold outlet passageway;   and a valve actuator for rotating the valve cylinder between a first angular position in which food material is pumped from a first pump into the valve cylinder and out through the manifold outlet passageway to the molding mechanism, an intermediate angular position in which food material is pumped simultaneously from the first pump and a second pump into the valve cylinder and out through the manifold outlet passageway to the molding mechanism, and a second angular position in which food material is pumped from the second pump into the valve cylinder and out through the manifold outlet passageway to the molding mechanism.   
     
     
       3. A high speed food patty molding machine, according to claim 2, in which the food pumps are positioned side-by-side, in which the valve cylinder includes two inlet openings, one for each pump, longitudinally displaced relative to each other and angularly displaced relative to the pump cavity outlets, and in which the outlet opening of the valve cylinder is an elongated longitudinal slot, angularly skewed relative to the manifold outlet passageway to balance the rate of feed to the molding mechanism for food material pumped from both pumps. 
     
     
       4. A high speed .[.foot.]. .Iadd.food .Iaddend.patty molding machine, according to claim 1, in which the supply means comprises a hopper for receiving food material, a conveyor for conveying the food material to one end of the hopper adjacent the intake openings of the food pumps, and a plurality of feed devices for feeding the food material to the intake openings of the food pumps in synchronism with the operation of the pumps. 
     
     
       5. A high speed food patty molding machine, according to claim 4, in which the conveyor comprises a belt forming the bottom of the hopper, a conveyor drive for driving the conveyor belt, and sensing means for interrupting the conveyor drive whenever the moldable food material accumulated at said one end of the hopper exceeds a given level. .[.6. A high speed food patty molding machine according to claim 1 in which the molding mechanism requires a given volume of food material in each cycle of operation, and in which the capacity of each food pump cavity is at least several times that given volume, so that each pump can supply the molding mechanism for a plurality of operational molding cycles without requiring an intake of additional food material..]..[.7. A high speed food patty molding machine, according to claim 6, in which the drive means for each food pump comprises a fluid pressure actuated power cylinder and a piston which advances the plunger and the food material in the food pump cavity during a part of each mold cycle in which the mold fills with food material and stalls against the food material trapped in the food pump cavity during a 
     
     
        part of each mold cycle after the mold is filled..]. 8. A high speed food patty molding machine, according to claim .[.7.]. .Iadd.1.Iaddend., in which the drive means for each fluid pump includes a low-pressure fluid supply for advancing the piston and plunger to an initial pumping position, a high-pressure fluid supply for advancing the piston and plunger beyond the initial pumping position, and changeover means for automatically changing over from the low-pressure supply to the high-pressure supply in response to the plunger stalling against food 
     
     
        material trapped in the pump cavity. 9. A high speed food patty molding machine, according to claim 8, in which the changeover means for each pump comprises a pressure-sensing device, connected to the power cylinder, for sensing a build-up of pressure in the cylinder when the pump plunger stalls against food material in the pump cavity while the piston is being 
     
     
        advanced by the low-pressure supply. 10. A high speed food patty molding machine, according to claim 9, in which the valve means is actuated to seal off one pump cavity from the manifold and open the other pump cavity to the manifold, and in which the plunger for said one pump is retracted to its ready position, in response to sensing of high pressure in both 
     
     
        power cylinders. 11. A high speed food patty molding machine, according to claim 1, in which the food pump cavities and the manifold comprise a common housing that includes the molding mechanism inlet, and in which the molding mechanism comprises: a sliding multi-cavity mold plate mounted on that housing for reciprocal movement between a filling position at which the mold cavities are aligned with the molding mechanism inlet and a discharge position at which the mold cavities are clear of the housing;   a mold cover positioned over the mold plate;   a knockout mechanism mounted on the mold cover;   and power-driven means for elevating the mold cover and knockout mechanism clear of the mold plate to allow cleaning of the molding mechanism and   
     
     
        replacement of the mold plate. 12. A high speed food patty molding machine, according to claim 1, in which said molding mechanism comprises a reciprocating mold plate, a crank drive for actuating the mold plate between filling and discharge positions, and a hydraulic cushion device incorporated in the crank drive.